With increasing development of science and technology, multimedia products and computers become essential in our daily lives. In the computer system, an input device plays an important role for communicating the computer host and the user. The common input device includes for example a mouse, a keyboard or a trackball. Among these input devices, the mouse is the most prevailing because it is very easy-to-use. When a mouse is held by a user's palm, the user may move the mouse to control movement of the cursor shown on the computer screen. In addition, by manipulating the buttons of the mouse device, the user may point and click a desired icon shown on the computer monitor or execute a corresponding function.
The configurations and the functions of a conventional mouse device will be illustrated as follows. FIG. 1 is a schematic cross-sectional view illustrating a conventional mouse device. As shown in FIG. 1, the mouse device 1 comprises a mouse base 10, a mouse case 11, a button 12, a circuit board 13 and a switch 14. The mouse case 11 is disposed on the mouse base 10 for sheltering the mouse base 10. When a user's palm is supported on the mouse base 10, the user may operate the mouse device 1. The button 12 is arranged on the mouse case 11. The button 12 has a pressing part 121 and a triggering part 122. The pressing part 121 is exposed to the outer surface of the mouse case 11 to be pressed by a user. The triggering part 122 is protruded into the space between the mouse base 10 and the mouse case 11. The circuit board 13 is disposed on the mouse base 10. The switch 14 is mounted on the circuit board 13, and arranged under the triggering part 122. In response to a downward force exerted on the pressing part 121 of the button 12 by a user's finger, the triggering part 122 is moved downwardly to trigger the switch 14. As such, a clicking signal corresponding to the pressed button 12 is generated.
Recently, the demands on the mouse devices become more stringent. For example, the operating comfort is an important factor of choosing a mouse device because most people use computers not only in the working time but also in the leisure time. Correspondingly, the mouse device is frequently used for most people. Generally, the downward force for pressing the button 12 of the mouse device 1 is constant when the mouse device 1 is operated and the button is pressed for a long time period. That is, a single downward force is employed to press the button. Since the downward force for pressing the button 12 fails to be adjusted, the procedure of pressing the button for a long time period usually incurs unacceptable fatigue of the user's hand. As the demand on comfort of using the mouse device is gradually increased, the conventional mouse device 1 is not satisfactory.
Therefore, there is a need of providing a mouse device to enhance the comfort of using the mouse device.